diff --git a/pretty.c b/pretty.c
index 1e1e21878c..2e47292407 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1857,7 +1857,8 @@ static size_t format_commit_item(struct strbuf *sb, /* in UTF-8 */
 	return consumed + 1;
 }
 
-static size_t userformat_want_item(struct strbuf *sb, const char *placeholder,
+static size_t userformat_want_item(struct strbuf *sb UNUSED,
+				   const char *placeholder,
 				   void *context)
 {
 	struct userformat_want *w = context;